diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 625eb1000..115ee7de6 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -61,6 +61,13 @@ repos:
   - repo: meta
     hooks:
       - id: check-useless-excludes
+  - repo: local
+    hooks:
+      - id: check-json-indentation
+        name: Check JSON Indentation Consistency
+        entry: pre-commit/check_json_indentation.py
+        language: python
+        files: \.json$
   - repo: https://github.com/astral-sh/uv-pre-commit
     # uv version.
     rev: 0.8.15
diff --git a/.pre-commit-hooks.yaml b/.pre-commit-hooks.yaml
new file mode 100644
index 000000000..db2bc0325
--- /dev/null
+++ b/.pre-commit-hooks.yaml
@@ -0,0 +1,8 @@
+- id: check-json-indentation
+  name: Check JSON Indentation Consistency
+  description: This hook checks that JSON files do not have mixed tabs and spaces for indentation.
+  entry: pre-commit/check_json_indentation.py
+  language: python
+  files: \.json$
+  types: [text]
+  verbose: true
diff --git a/.taskcluster.yml b/.taskcluster.yml
index 22e10e44d..3c12b6353 100644
--- a/.taskcluster.yml
+++ b/.taskcluster.yml
@@ -48,6 +48,7 @@ tasks:
             - "git clone --quiet ${repository} bugbot &&
               cd bugbot &&
               git -c advice.detachedHead=false checkout ${head_rev} &&
+              chmod +x pre-commit/check_json_indentation.py &&
               pip install --quiet -e '.[test]' &&
               pre-commit run --all-files --show-diff-on-failure &&
               tox -e $TOX_ENV &&
diff --git a/pre-commit/check_json_indentation.py b/pre-commit/check_json_indentation.py
new file mode 100644
index 000000000..b31b277c4
--- /dev/null
+++ b/pre-commit/check_json_indentation.py
@@ -0,0 +1,34 @@
+#!/usr/bin/env python3
+import sys
+
+
+def check_json_indentation(filename):
+    with open(filename, "r") as file:
+        lines = file.readlines()
+
+    tabs_found = False
+    spaces_found = False
+
+    for line in lines:
+        stripped_line = line.lstrip()
+        if stripped_line and line.startswith("\t"):
+            tabs_found = True
+        elif stripped_line and line.startswith(" "):
+            spaces_found = True
+
+        if tabs_found and spaces_found:
+            print(f"Error: {filename} contains mixed tabs and spaces for indentation.")
+            return False
+
+    return True
+
+
+if __name__ == "__main__":
+    files_to_check = sys.argv[1:]
+    exit_code = 0
+
+    for json_file in files_to_check:
+        if not check_json_indentation(json_file):
+            exit_code = 1
+
+    sys.exit(exit_code)